GILBRICH, W.H., STRUCKMEIER, W.F., RICHTS, A., DUSCHER, K., GÜNTHER, A., PHILIPP, U. & WINTER, P. (2014): 50 Years of Hydro(geo)logical Mapping Activities Under the Auspices of UNESCO, CGWM, IAH and BGR. - 79 p.; UNESCO, Paris. (PDF, 7 MB)
Date of issue: May 15, 2015